The present invention relates to an operating device for window openers, screening arrangements and similar devices and of the kind stated in the introductory part of claim 1.
An operating device of the known type comprises a rod with an end hook intended for releasable engagement with an eye having an aperture, the area of which is essentially larger than the cross-section of the hook. With this operating device, it is relatively easy to bring the hook into engagement with the eye, but on the other hand, considerable attention is required to avoid that the hook disengages the eye, in particular if the rod axis forms an angle with the rotational axis of the eye.
DE 4 231 504 discloses an operating device comprising an operating rod with an end hook shaped as the FIG. 7, and a coupling element with an annular eye, the aperture of which has an area which is a little larger than the cross-section of the hook. This operating device assures a secure engagement between the hook and the coupling element, however, it is very difficult to bring the hook into engagement with the eye of the coupling element as the area of the aperture is only a little larger than the cross-section of the hook.
The object of the invention is an operating device which can be operated by operating rods provided with hooks of different shapes and which is simple to bring into engagement between the hook and the coupling element and at the same time assures a secure engagement even if the rod axis forms an angle with the rotational axis of the coupling element.
According to the invention, this is obtained in that the annular eye in connection with said aperture comprises a narrowed additional aperture which, at least upon reception of the hook-shaped operating element as a result of a pull, securely engages the operating element.
An operating device of this kind permits an easy insertion of the hook-shaped operating element into the essentially annular eye of the coupling element, as the eye has an aperture with an area essentially larger than the cross-section of the hook-shaped operating element. Subsequently, the hook-shaped operating element can be moved to the narrowed additional aperture whereby a secure engagement during operation is obtained even if the rod axis forms an angle with the rotational axis of the operating element.
The engagement can according to the invention be further improved by providing the coupling element in one or both of the annular profiles with at least three hinge portions. By this design, a squeezing effect can be obtained around the hook-shaped element in the additional aperture when at the same time, a pull of the hook-shaped element is effected in a direction away from the large aperture.
According to an alternative embodiment, the engagement can be improved by producing the entire or a part of the annular profile around the additional aperture from an elastic material.